Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover the safety profile (readOnlyHint, destructiveHint=false, openWorldHint), and the description adds real value beyond them: an auth requirement that applies even to public agents, a zero-cost statement, and an interpretive caveat that returned-after-delivery is observed sequence rather than causal evidence. It stops short of rate limits or response-shape detail.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Four dense sentences, front-loaded with what is read, then auth, then the interpretation caveat. Slightly clipped phrasing but no sentence is filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return values need not be spelled out, and the description covers the non-obvious parts: auth precondition, cost, and the causality caveat. Only pagination/volume behavior and explicit alternative-routing are missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 0% with two required parameters, so the description carries the burden. It clarifies that an owner key is required even for public agents, which loosely maps to api_key, but it never names either parameter or explains agent_id, leaving the semantics largely undocumented.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb (read) and resource (agent reengagement), and enumerates what is returned: reminder settings, next eligibility, deliveries, observed returns. It clearly contrasts with the configure_agent_reengagement sibling by being the read counterpart, though it never names that sibling explicitly.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is only implied — an agent can infer this is the read-side of reengagement, and the description adds a precondition (owner key required even for public agents) plus a cost note ('read costs zero'). But there is no explicit when-to-use vs alternatives guidance and no named sibling to route against.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.